From owner-freebsd-current@FreeBSD.ORG Sun Dec 14 17:19:01 2014 Return-Path: Delivered-To: current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 984C1D3; Sun, 14 Dec 2014 17:19:01 +0000 (UTC) Received: from mail.karels.net (mail.karels.net [63.231.190.5]) by mx1.freebsd.org (Postfix) with ESMTP id 47B766B9; Sun, 14 Dec 2014 17:19:00 +0000 (UTC) Received: from mail.karels.net (localhost [127.0.0.1]) by mail.karels.net (8.14.7/8.14.7) with ESMTP id sBEHIr8g078422; Sun, 14 Dec 2014 11:18:53 -0600 (CST) (envelope-from mike@karels.net) Message-Id: <201412141718.sBEHIr8g078422@mail.karels.net> To: Ian Lepore From: Mike Karels Reply-to: mike@karels.net Subject: Re: simple task to speed up booting In-reply-to: Your message of Sun, 14 Dec 2014 07:52:11 -0700. <1418568731.935.8.camel@freebsd.org> Date: Sun, 14 Dec 2014 11:18:53 -0600 Cc: Poul-Henning Kamp , current@freebsd.org X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 14 Dec 2014 17:19:01 -0000 > > On Sun, 2014-12-14 at 10:32 +0000, Poul-Henning Kamp wrote: > > The rotating swirlie ('-/|\') in the loader accounts for a surprisingly > > large part of our boot time on systems with slow-ish serial consoles. > > > > I think right now it takes a step for each 512 byte read, reducing that > > to once every 64kB or even 1MB would be an improvement with the kind of > > kernel sizes we have today. > > > I experimented with that a while ago using the attached patch and was > disappointed with the results. As I vaguely remember it, a divisor of 8 > looked fine, but had no significant speedup. With a divisor of 32 the > difference was measureable (only like 1.5 seconds or so faster), but it > gave the impression that something was wrong, and the overall perception > was that it was slower rather than faster, despite what a stopwatch > said. > I was testing at 115kbps, maybe at 9600 it would be significant. I > don't understand why anything these days is still defaulting to 9600. > It's the 21st century, but we never got the George Jetson flying cars we > were promised, and apparently we're never going to break loose from the > standards set by accoustic-coupled modems. AFAIK, accoustic-coupled modems topped out at 300 baud; that's the fastest one I've used, anyway. Defaults are hard to change, though. Mike